1. Field of the Invention
The present invention relates to a pneumatic tire, more particularly to a tread pattern for winter tire.
2. Description of Background Art
In general, snow tires are provided with block-type tread patterns, and the blocks are provided with a great number of sipes. If the number of sipes in a tread portion are excessively increased, as the blocks are decreased in the rigidity, the amount of deformation or leaning of the blocks during running increases. Therefore, the ground contacting area and grip power are decreased, and as a result, the steering stability is deteriorated and uneven wear is liable to occur on the blocks. cornering performance on ice is important factor for the snow tires as well as straight running performance, e.g. traction, braking distance and the like. As explained above, if a great number of sipes are formed, the difference in the grip power between straight running and cornering is liable to become increased. Therefore, a vehicle provided with such tires is liable to become unstable in its behavior in a time of transition from straight running to cornering.